In the factory building option of the map editing tools, factories with a distribution weight set to zero are not shown.I'd like to have them included to be able to have factories which are not build automatic but can be added manually.

Can't find the location in the source where this list is created and displayed.Anyone knows where that is done ?

These obsolete factories have nothing to do with the in-game timeline. They are factories that existed in earlier version of the pak set, but with have been succeeded by other developments in later versions.